E-544 August 1941
TOXICITY OF PYRETHRINS I AND II IN KEROSENE TO THE AMERICAN COCKROACH
By E. R. McGovran and E. L. Mayer, Division of Control Investigatin,
and Fred Acree, Jr., Division of Insecticide Investigations
The toxicity of pyrethrins I and II to cockroaches has been given some study. Staudinger and Ruzicka (5)1/ tested synthetic pyrethrins I and II on lots of five cockroaches. The pyrethrins were diluted with flour to 1:500, 1:5,000, and 1:25,000. The action of the two pyrethrins was observed to be similar except at 1:5,000, where pyrethrin I killed four of the five roaches treated and pyrethrin II killed only two of the five treated, indicating that pyrethrin I was more effective. The paralytic or knockdown effect of the pyrethrins on the insects was observed by these investigators but they did not record any difference in the two pyrethrins in this respect. Gnadinger and Corl (1) treated cockroaches, Blattella germanica (L.) (Blatta germanica), with alcohol solutions of pyrethrins dispersed as colloidal solutions in water. Twenty-four hours after treatment the result from one concentration of pyrethrin I was recorded as "none dead, all disabled"; in comparison with this, the result from the same concentration of pyrethrin II was recorded as "none dead, all recovered." These investigators concluded that pyrethrin I was slightly more active than pyrethrin II. These results indicated that an investigation of the action of pyrethrins I and II on the American cockroach (Periplaneta, americana (L.)) might be useful in connection with the practical control of this species by the use of pyrethrum sprays.
This investigation also seemed desirable since Sullivan, Haller, McGovran, and Phillips (6) have shown that pyrethrin II was more effective in causing knockdown of houseflies (Musca domestica (L)) than pyrethrin I, although the latter caused higher mortalities.
1/The numbers in parentheses refer to the literature cited at the end of this circular.
Preparation of Pyrethrin Solutions
The pyrethrin concentrates used in the preparation of the kerosene solutions were obtained from petroleum ether oleoresins of Japanese pyrethrum. The separation of the pyrethrins was achieved by partition between acetic acid and petroleum ether as described by LaForge and Haller
(3). Further purification of the concentrate high in pyrethrin I ,as accomplished by distilling it in a molecular still. The pyrethrins wre determined by the hydrogenation method of LaForge and Acree (2). Sol' tion 1, in which pyrethrin I predominated, was prepared by dissolving 0.50 gra. of a
concentrate containing 85 percent of pyrethrin I and 15 percent of pyrethrin II in a highly refined kerosene (Deobase) and diluting the solution to 100 cubic centimeters with the same solvent. Solution 2, which was high in pyrethrin II, was prepared similarly from 0.50 gram of a concentrate containing 95 percent of pyrethrin II and 5 percent of pyrethrin I. Solution 3 containing approximately equal parts of pyrethrins I and II, was prepared as above from 2.0 grams of a concentrate that contained 12.4 percent of pyrethrin I and 12.8 percent of pyrethrin II. These stock solutions, each containing 5 milligrams of total pyrethrins per cubic centimeter, were then diluted with the kerosene to the desired concentration.
Biological Testing Procedure
After the roaches had been weighed the solutions containing the different concentrations of pyrethrins I and TI in refined kerosene were applied with a micropipette, as described by McGovran, Phillips and Mayer
(4). The wings of the roaches were held apart so that the liquid v:as applied to the surface of the dorsal integument upon which it spread rapidly. Each female roach was treated with 0.006 ml. of liquid, and each male with 0.0045 ml. The volume of liquid applied was approximately proportional to the average weight of the individuals and was very close to 0.005 .l. per gra.. of body weight for both males and females. Three roaches, either all sales or all females, were treated in each test. Each test was repeated the number of times shown in tables 1 to 3. After treatment the roaches were released in cages with food and water. The knockdown or paralysis which consisted of the insect being unable to stand or crawl and usually lying on its back with its appendages moving when 'the cage was shaken, was recorded 15, 30, 45, 60, 90, and 120 minutes after the insecticide was applied. The total of mortality plus knockdown was recorded 24 hours after treatment
and the total mortality at the end of 4 days was recorded as shown in tables 1 to 3. The reactions of the male roaches to the insecticides were so different from those of the females that the results were recorded separately.
The weighing of 322 female roaches in lots of 5 to 8 insects each revealed the average weight of the female roaches to be 1.213 grams. The average weight of the 178 males that were weighed was 0.914 gin.
The data on the knockdown and mortality of the roaches are given in tables 1, 2, and 3.
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Discussion of Results
The insecticides used in these tests were in all cases mixtures of pyrethrins I and II and other materials, Thus while the effect produced
w;as probably caused mainly by the predominant pyrethrin present, the other pyrethrin which was always present, may have influenced the results szbitainied.
A more rapid knockdown of the coaches occurred with the ii-sect-icide
c uyrethri.- TI (5 percent pyre thrit- I and 95 percent pyrethL'. II
i.with the matec-rial rich in pyrethrin 1 (85 percent pyrehrn1ad5 p.ericent pyrethrin II) except in series 6, table 2.
The greatest difference in. kiockdo,.vi of *. 'emale roaches occurred .5~nue after treatment,. and the difference (Aecreased in the cas-e of the
1-:5 mgs. per ml. solution until it was not stat-'slically significantly afte r 50C rinutes.V/ The differences in knockdown -;f female roaches ca'Jbyie
_0 mg, per ml. solution w ere not staisii-c'a,1y s igniJf icanE t _vl the .5-iinteknockdownl by the 0. 5 mg. per n.l. s iuti)ns showed a. sia ~cally )-C: 2ficant d-feec. Tekncdw fni roaches follows, .3 ame
geral. pattern. except. at the lowest concentricio oa yrtr, 0
Super ml. ) where the knockdown of the ii ectii3o high in pyre 77 IWas
uprisingly low at first hut increased tc aov that of th ue ide
1,i4gh J:, pyrethrin I by the 90-minute ebservatici It appears- t7ia t o
concentration the threshold con,,centratiorc of pyrathriii II thtan he
rapid1 knocckdown has not bee:n reached. Th~ lockdownwn plus iit.al~Y at 24 hours showed some decrease from the 2-orkokonin all except
ne~s4, table 3, and a very large decide K all instance.C,, .- c the
-ectcidehigh in pyrethrin IT was used. There lot tfer "*cc wr
_,rt sically significant. A f ew roaches thha ore, t reacd v li, .er
~c,-n Lrations of pyre thrins recovered in: the secondd hour afe rz~et,
The data presented in tables I anid 2 record compar. soni. uO4 rthe rs rial ities caused by insecticides high iK py tris 1 andl II, ufter
-,rea tmen t. These comparisons show that a l x~vl low mO-n from Practical point of' view, namely 77 v n 5 percentan 3 c:u 17
pecetfo fmlean~d 62 versus 42 pEcc 12vrsz.7p. Kfor
ho males, the insect icide that, was rih yr -hin I caLusod,, h~h~ rtaltisalthough only the first of ths Wtc.csis statK 'cyhih
1, -ignificant However, ini cont rasti ro s u It.01 ot., !lothse
Sof' mortality, when suf ficient, pyretl-. was ued to Oc,,- I ra ity
*0 ercent or more, the insoctici les ml z.r highi in, pycet:, T or -.in I! gave about t equal mortality 20vit 83 pc r,.t n vrsus
c-ent on female and maerahsrseivl.These dt dcaethat
>ru.pnrisol. of I ths w netbd.,h a aea a tivl OW
~~Mr, I1 of motty fr7i the pr1 c10 :1 I' ivw wanoa *crte
i..of the mortlitiesteesl .~c uswud~i*ea
h le hvels of ~fcI ~~Cfwc u ~n'yzprih~tnetiI e
?/The authors wi o express. h(ir iu .-. Dr, F, ori Uyc his
t ons on the statistAical I reitota.d
desired in the practical control of insects. That i, under the coni.0 of these tests it appears that after a certain concentration was reate insecticide high in pyrethrin II was just as effective in causing :or of the roaches as the insecticide high in pyrethrin I.
The insecticide used to obtain the data in cable 3 had, in addition to the pyrethrins present. appreciable quantities of pyrethrum olece.in as shown in the footnote under table 3. A compcarison of the results oLt with this insecticide with the results given in 6LI 1 I and 2 on the
of total pyrethrins indicates that this insecticide was more effect The higher toxicity of this insecticide woald indiote that the meth purifying the pyrethrins used in obtaining the daca in tables 1 and 2 : reduced the toxicity of the total pyrethrins prnent somewhat or 1tha. the materials in the pyrethrum oleoresins other than pyrethrins I and II I: 1 increased the toxicity of the insecticide. These dnta also show that the female roaches were approximately twice as resistant to this pyrethr : insecticide as the males. The data in tables 1 and 2 also indicate this sa e relationship in resistance between male and female adult American cockroaches
A comparison of the 120-minute knockdown, which in most series given in tables 1, 2, and 3 was the highest knockdown observed, with the mortality
4 days after treatment shows that in all but two instances some recovery occurred. In tables 1 and 2 more recovery always occurred with roaches treated with the insecticide high in pyrethrin II than with that high :n pyrethrin I. This resulted from two factors; first, in five of the six
pairs of series of tests run the pyrethrin II gave thc higher knockdown, and in the sixth pair of series the knockdown was equal; and second, in four of the six pairs of series the pyrethrin I caused higher mortalities, in one tile mortalities were equal, and in the other a higher mortality was caused by
pyrethrin II than by pyrethrin I. The insecticide used in obtaining the data in table 3 is more nearly like the pyrethrum spray that is used commercially to control roaches than are the other two insecticides discussed, but it also shows some recovery of the roaches knocked down in 120 minutes in five of the six series of tests, although the differences are not statistically significant.
Another point of interest is the 100-percent knockdown obtained in series 1 and 2 in table 3. Where 1.5 mg. of total pyrethrins per ml. was used only 3 percent survival occurred, compared with 17 percent survival where 1.0 mg. per ml. was used, indicating that the percentage of mortality
among roaches may vary even when a 100-percent knockdown is obtaiucd.
Kerosene solutions rich in pyrethrin II (5 percent pyrethrin I, 95 percent pyrethrin II), when applied in measured volu-.es to adult American cockroaches (Periplaneta americana) with a micropipette, caused more rapid and higher percentages of knockdown than similar insecticides rich in pyrethrin I (85 percent pyrethrin I, 15 percent pyrethrin II) Maximum knockdo,,n was reached in from 30 to 120 minutes.
UNIVERSITY OF FLORIDA
3 1262 09230 4046
The insecticide that was rich in pyrethrin I caused higher mortalities at concentrations that caused 17 to 77 percent mortality, but with more concentrated solutions that killed 80 to 83 percent of the roaches the mortalities caused by prethrins I and II preparations were about equal. Female roaches were about twice as resistant to the pyrethrum preparations as male roaches. In 16 of the 18 series of tests made some of the roaches that were knocked down 2 hours after treatment recovered and were living 4 days later.
(1) Gnadinger, C. B., and Corl, C. S.
1929. Studies on pyrethrum flowers. I. The quantitative determination of the active principles. Jour. Amer.
Chem. Soc. 50: 3054-3064. October.
(2) LaForge, F. B., and Acree, Fred, Jr.
1941. Determination of pyrethrins. A method for the quantitative determination of pyrethrins based on cleavage on hydrogenation. Soap and Sanitary Chemicals 17 (1): 95-98.
(3) -------------and Haller, H. L.
1935. Constituents of pyrethrum flowers. II. Isolation of pyrethrin II. Jour. Amer. Chem. Soc. 57: 1893-1896.
(4) McGovran, E. R., Phillips, G. L., and Mayer, E. L.
1940. A measured drop method of applying liquid insecticides.
U. S. Dept. Agr., Bur. Ent. and Pl. Quar. ET-165 (multigraphed).
(5) Staudinger, H., and Ruzicka, L.
1924. Insektenttende Stoffe X. Uber die Synthese von Pyrethrinen, Helvetica Chimica Acta 7 (3): 448-458.
(6) Sullivan, W. N., Haller, H. L., McGovran, E. R., and Phillips, G. L.
1938. Knockdown in fly sprays. Comparison of toxicities of pyrethrins I and II as determined by method for knockdown and mortality, Soap and Sanitary Chemicals 14 (9): 101-105, illus.